Coating masses, in which aliphatic di- or polyisocyanates are used as the isocyanate component, are particularly suitable for the production of mechanically and/or climatically resistant coatings on objects made of wood, concrete, steel, etc. Compared with two-component polyurethane coating masses, they have the advantage that they harden through reaction with the moisture contained in the ambient air, i.e., it is not necessary to add a separately supplied hardener prior to their use. Up until now, however, it has only been possible to apply them to the substrate in relatively thin dry layers up to 100 microns thick, because bubbles tended to form in thicker layers and/or the coating adhered poorly to the substrate and/or the hardened layer exhibited buckling and/or cracking and/or opacity. However, the protection provided against mechanical and/or atmospheric influences by such thin coatings is often not as good or not as durable as desired.